Dieting Factors that Affect Hypertension

There is some evidence that an increase of potassium, calcium and magnesium in the diet may help to lower blood pressure. But a great deal of research still has to be done into this subject and it is too soon to recommend that people take mineral supplements for the control of hypertension. Similarly, although it is thought that omega-3 and omega-6 polyunsaturated fatty acids may decrease blood pressure, further research is needed before recommendations can be made.

Alcohol as a risk factor

Excessive alcohol consumption - defined as more than two drinks daily - is linked to both high blood pressure and high cholesterol levels. HDL (cholesterol) levels tend to increase with an increase in alcohol intake, but the risks associated with a moderate alcohol intake (1-2 beers or 2 glasses of wine or 2 tots of whisky or brandy per day) appear to be no higher than those of abstainers; however, heavy drinkers have increased levels of most of the coronary risk factors.

Interestingly, results of the CORIS (Coronary Risk Factor) Study - which involved men as well as women - showed that blood pressure and cholesterol levels tended to be slightly lower in light drinkers than in both heavy drinkers and in those who don't drink at all. A moderate alcohol intake therefore seems to be associated with lower blood pressure levels and also appears to protect the individual from cardiovascular risk and mortality. However, the serious medical and social problems associated with alcoholism should discourage any increase in alcohol consumption.

Breaking new ground

As research into the causes of heart disease continues, additional factors come to light which appear to be relevant in the prevention of CHD. Sometimes, however, it can take years before a suspected link is proved scientifically.

The fat/fibre connection

Recent studies on the role of dietary fibre in lipid (fat) metabolism have shown that fibre can have a positive effect by interfering with the body's absorption of fat. It has also been proved that dietary fibre - and especially water-soluble fibre, which is found in dried legumes, oats, oat bran, apples and oranges - has a cholesterol-lowering effect. It is not yet clear what precise mechanism is involved. Because of its obvious benefits in this and other areas, we should all increase our intake of dietary fibre to at least 20-30 g a day. This can be achieved by eating unrefined cereals, more wholewheat bread, fruit and vegetables and by substituting dried legumes (such as beans or lentils) for animal protein at least once per week. An additional benefit of a high fibre diet is that it is also high in complex carbohydrates - a good substitute for fat in the diet.

The vitamin controversy

The role of vitamins in the prevention and treatment of coronary heart disease is controversial and much research is still being done in this area. It has been suggested - but not proved conclusively - that ascorbic acid (vitamin C) and vitamin E may have a protective effect in the early stages of atherosclerosis (blockage of the arteries). Niacin (one of the B-complex vitamins) is often combined with cholesterol- lowering drugs used to treat high blood cholesterol levels. However, there is not sufficient proof as yet to suggest that vitaminsupplementation will lower anyone's risk of developing coronary heart disease.

Cholesterol-lowering Eating Plan

The Heart Foundation has given the following guidelines for achieving the goals of the Prudent Dietand maintaining low blood cholesterol levels:

• Eat less fat and substitute unsaturated for saturated fats. One of the major goals of a cholesterol-lowering eatingplan is to eat less total fat, not only because this is an effective way to reduce the amount of saturated fat in your diet, but also because it helps to decrease your total daily kilojoule intake.
• Cut down on foods of animal origin. Dietary cholesterol found in these foods raises blood cholesterol levels significantly.
• Eat more complex carbohydrates, especially those rich in fibre. Good sources include wholewheat bread, brown rice, pasta, cereals, dried peas and beans, fruit and vegetables. (Fibre - especially the water- soluble type found in oats, oatbran, some fruit and legumes - may even help to reduce blood cholesterol levels.)
• Avoid being overweight. To achieve or maintain your ideal body weight, your kilojoule intake should not exceed the number of kilojoules your body needs.
• Use less salt (sodium). A high sodium intake may cause high blood pressure. Cut down on the salt you use at the table and in the preparation of food. Be aware of the 'hidden' salt in commercial foods.
• Limit your alcohol intake. A moderate intake is regarded as two drinks (2 glasses of wine, 2 x 25 ml tots of spirits or 1-2 beers) per day. If you are overweight, avoid alcohol entirely.

Combat Heart Disease

The danger of heart disease can and should be combatted on a daily basis in every home in South Africa - in fact, only in this way can we hope to lower our tragically high CHD statistics. Here are some tips for preventing the development of two of the major offenders - high blood cholesterol levels and hypertension - that you can put into practice in your own kitchen:

To cut back on saturated fats:

1. Choose poultry, fish and lean cuts of meat more often and remove the skin and trim the fat from meat.
2. Drink skim or 2% milk rather than the full-cream version. Eat low-fat cheese instead of hard cheese such as Cheddar.
3. Use tub margarines and/or vegetable oils (sunflower, olive oil) that are high in unsaturated fat instead of butter, lard and hard margarine - which are all high in saturated fat.
4. Cut down on commercially prepared and processed foods made with saturated fats and oils (such as biscuits, pies and pastries).

To cut down on dietary cholesterol:

• Eat less organ meat such as liver, brains and kidneys.
• Eat fewer egg yolks and try substituting two egg whites for each whole egg in recipes.

To increase complex carbohydrates:

• Eat more whole grain breads and cereals, pasta, rice and legumes (dried peas and beans).
• Eat fruit and vegetables more often.

To lose weight:

• Eat fewer kilojoules daily (cutting back on fat will really help).
• Burn up extra kilojoules by exercising regularly.

To reduce your total salt intake:

Remove the salt cellar from the table.

• Gradually reduce and/or omit salt in cooking (see below).
• Avoid foods with a high sodium content - the major culprits are canned, processed and convenience foods, such as bacon, sausages, salami, potato crisps, salted nuts, salty biscuits, powdered soups, gravy powders, stock cubes, sauces and dressings.
• Read food labels and avoid foods with added salt/sodium.

To cut back on alcohol:

• Choose low alcohol wines or beer.
• Dilute white wine with mineral or soda water.

Cutting salt out of cooking

You can get used to cooking with very little or no added salt by:

• Using garlic, dry mustard, peppers, onions, mushrooms and tomatoes to add flavour to meat and vegetable dishes in place of salt.
• Adding a little wine to casseroles and stews. The alcohol willevaporate during cooking, but the flavour remains.
• Adding sliced lemon or lemon juice to white meats and fish.
• Using herbs (such as basil, origanum, sage and thyme) and spices (such as cardamon, cinnamon, cumin and nutmeg) for flavour.

What is dietary fibre?

Over the years, many terms have been used to describe the indigestible residue that remains in the digestive tract after all the available nutrients have been absorbed. In fact, when research on the subject began in earnest, one of the first problems the researchers faced was agreement on terminology and definition. It was decided that the terms 'crude fibre', 'roughage' and 'fibre' were inappropriate because some components of dietary fibre are water soluble (see below) and not fibrous or 'rough' at all. The term 'dietary fibre' is however firmly established in the history of nutrition and in the public mind and it was agreed that this should continue to be used.

Hugh Trowel and Denis Burkitt, two British doctors working in East Africa and pioneers in dietary fibre research, recognised early on that fibre comprises a group of substances, all either polysaccharides or lignin. Polysaccharides consist of a multiple grouping of glucose units (as in starch) which are however impossible for humans to digest, while lignin is a coarse, 'woody' compound found in the gritty part of pears and vegetable stalks. Unfortunately, the method they used to determine the quantity of this material also measures a variety of other substances (including some starch) which resist digestion in the small intestine and are only handled by the large intestine later.

Researchers from the Dunn Clinical Nutrition Centre in Cambridge England, developed a new and more appropiate method (the Eglyst method) of analysis, in which starch is completely removed and dietary fibre measured as the non-starch polysaccharides. This has led to a redefinition of dietary fibre as NSP (Non-Starch Polysaccharides). Lignin, although not a polysaccharide, is also regarded as dietary fibre; it is bound to the cell wall and probably contributes to the effects of NSP on body functions. It is however very difficult to measure and amounts present in edible foods are believed to be small.

Soluble vs insoluble fibre

A more practical classification, based on solubility and differences in effects in the body, is that of water soluble and insoluble dietary fibre. Insoluble fibre binds water and has a 'bulking' effect, whereas soluble components are inclined to form gels in water and are therefore also referred to as 'gel-forming' dietary fibre. Interestingly, recent research has shown that water soluble fibre (found in oats, oat bran, dried legumes and some fruit) has a significant cholesterol-lowering effect.

Extraordinary oats

The well-known quip that oats is 'a grain which in England is generally given to horses but in Scotland supports the people' gives no clue as to the diverse nutritional benefits of this cereal product. Firstly, the protein present in oats is of good quality and, coupled as it is with fibre and carbohydrate, it provides a breakfast with a high satiety value at a low price. Foods which - like oats - banish hunger for lengthy periods are particularly useful for schoolchildren, who won't feel the need to dash to the tuckshop at first break!

But this does not mean that oats is strictly for the kids, since the type of fibre which oats contains is of particular significance. Dietary fibre, or roughage, is made up of insoluble fibre (which forms bulk in the digestive tract and plays an important role in promoting peristalsis and preventing constipation), and soluble or gel-forming fibre. The fibre in oats is predominantly of the latter type, which has been shown to play a useful role in lowering blood cholesterol levels. It does this by binding with cholesterol in the digestive tract and preventing its absorption into the bloodstream. In addition, it slows down digestion and, at the same time, the release of glucose into the bloodstream, which is of special benefit to diabetics. Soluble fibre also promotes bacterial action in the digestive tract, helping to prevent constipation, and may well play a role in reducing the risk of bowel cancer.

How fibre affects the body continue...

Appendicitis

Appendicitis is inflammation of the appendix, the small blind-ended tube at the beginning of the large bowel. Although the underlying causes of appendicitis are not clearly understood, there is evidence that regular intake of fibre may prevent the development of the disease.

Hiatus hernia, varicose veins and piles

Many doctors believe that abdominal straining due to constipation encourages the development of conditions such as hiatus hernia (where the top of the stomach is pushed upwards, out of the abdomen and into the thoracic cavity), varicose veins and haemorrhoids (piles). It is often necessary to have surgical treatment for these conditions. Treating constipation with high fibre diets and, as a result, avoiding straining, may prevent these problems and may even reduce the need for more drastic treatment in some cases.

Coronary heart disease (CHD)

Coronary heart disease is the most common cause of death in affluent Western countries (see page 151). A large number of factors influence the development of the disease, of which raised blood cholesterol levels, high blood pressure and hypercoagulability (the tendency of the blood to clot too easily) are probably the most important.

Researchers believe that high-fibre, low fat diets protect against CHD by lowering blood cholesterol and probably also by decreasing blood pressure and the clotting ability of blood. It is especially the water soluble or gel-forming dietary fibres - found in oats, legumes and some fruit and vegetables - which help to lower cholesterol levels. While it should be borne in mind that diet is but one of the many factors which influence the development of CHD, it is also one of the controllable ones.

Diabetes mellitus

There are two forms of diabetes mellitus, a disease characterised by the excretion of glucose (sugar) in the urine (see What is diabetes? on page 175). Both forms are today treated with a high carbohydrate, high fibre, low fat diet. Fibre in the diet normalizes the body's response to dietary carbohydrate (glucose tolerance). A regular high intake of dietary fibre also improves insulin function by increasing the sensitivity of muscle and fat cells to the hormone.

Gallstones

The body manufactures these crystalline substances when the amount of cholesterol in the bile is so high that the bile salts cannot keep it in solution. The stones may block bile ducts between the liver and gall bladder or between the gall bladder and small intestine, resulting in severe pain and even jaundice. As in the case of other diseases of affluence, a number of factors may contribute to the development of gallstones. It has however been shown that high fibre intakes stimulate the production of those bile salts which keep cholesterol in solution, thus decreasing the risk of gallstone formation. Populations who follow high fibre diets have a significantly lower risk of the disease than those on the average refined Western diet.

To what degree is fibre involved?

Although research has proved that dietary fibre has a positive effect on body functions in general, the degree to which it is involved in the risk and development of the above diseases is still unclear. Studies are hampered by the fact that a variety of causes play some role and also because high-fibre diets differ in more than one respect from low-fibre ones. For example, they usually have a lower fat content - especially saturated fatty acids from food of animal origin - and are higher in vitamins and minerals. These factors could add to the beneficial effects seen in people who eat a high-fibre diet.

What is diabetes?

Diabetes is a disorder in which the pancreas cannot produce enough insulin, a hormone which prevents blood sugar levels from rising too high, or in which the insulin that has been produced does not function properly. It does this by helping body cells to take up glucose - either to metabolise to energy or to store as glycogen or fat.

If an individual manufactures too little insulin, there are two possible forms of treatment: The young, more severely affected diabetic can only survive if given daily injections of insulin for the rest of his or her life. However, if diabetes develops at a later age, treatment with pills is usually effective. These pills are not insulin; they are essentially compounds which give the pancreas the necessary stimulus to produce more insulin to cope with the carbohydrate (sugars and starches) which the individual eats. Because sugar causes a dramatic rise in blood sugar levels, diabetics should obviously avoid it in their diets; indeed, they should avoid all unnecessary food in general if they are overweight, as not only is the insulin requirement related to food intake, but excess weight has an aggravating effect on the condition. Obese diabetics who develop the disease in later life can often be treated by diet alone.

A low fat, high fibre intake - which 'dilutes' the contents of the digestive tract - slows down the passage of glucose into the blood stream and hence the elevation of the blood sugar is less dramatic.

How fibre affects the body

The whole subject of food residue is a complicated one because of the variety of indigestible compounds and the different ways in which they influence the digestive and absorption processes in the body. In the simplest terms, dietary fibre acts in the digestive tract by binding or absorbing water and other substances, thus causing 'bulking' of the contents of the gut. It influences the speed with which food moves through the various parts of the digestive tract. However, the ways in which fibre affects digestion, absorption and the movement of food in the digestive tract are diverse, far-reaching and not always well understood. To illustrate this, fibre in the diet may affect blood sugar levels, the production of bile, the transport of cholesterol in the body and your chances of developing colon cancer. It can even affect the hormonal responses to a meal.

A variety of factors influence the effect of a particular fibre or high- fibre food. The chemical composition of the fibre, its particle size, the age of the plant source and methods used in the processing of the food, all affect the physical properties of the fibre. It is these characteristics which account for the different functions of fibre in addition to its main effect of causing in^creased bulk formation in the digestive tract.

Fibre effects are also influenced by the total composition of the meal and the amount of fibre in it. Short-term effects - for example on the blood sugar level - can be seen immediately after a person has eaten a single high-fibre meal. Long-term effects, such as lowering of blood cholesterol levels, occur only after a regular and prolonged intake of fibre. The effect of fibre in the different parts of the digestive tract (stomach, small and large intestine) also differs and may vary between individuals.

Fibre and the diseases of affluence

As already mentioned, research on dietary fibre was initially stimulated by studies which showed that population groups who follow high-fibre diets suffer far less from the 'diseases of affluence' - the medical term used to describe degenerative diseases and disorders which have been linked to a prosperous Western lifestyle. Among these are colon cancer, appendicitis, gall stones, varicose veins and constipation. Their causes are many; what has been established is that a variety of environmental factors, including dietary habits, can trigger these diseases in people who are genetically 'vulnerable' to them. This explains why they tend to run in families and why some people, even though they follow a Western lifestyle, do not develop a particular disease.

Let's look at those diseases which are known to be associated with the amount of fibre in our daily diets:

Constipation

Constipation is probably one of the most common disorders in the world and is also the cause of other diseases (see diverticular disease and colon cancer below.) It can be defined as the relatively slow movement of unduly firm waste matter through the large bowel, which results in the infrequent passing of small, hard and dry stools - often accompanied by straining.

Including enough fibre in your diet prevents constipation in various ways. Firstly, fibre is not digested in the small intestine. It therefore moves to the large bowel where it has a bulking effect, increasing the volume of the bowel content. Because it binds water, fibre prevents the absorption of water from the large bowel to some extent, ensuring that the contents remain large in volume and soft in consistency. Fibre also stimulates the growth of microbes in the large bowel, which contributes to larger, softer stools. The larger volume in the bowel stimulates peristaltic movements and eases the process of defecation so that straining is not necessary. In addition, during the partial fermentation of fibre in the large bowel by microbial enzymes, substances such as methane and hydrogen gasses, water and the short-chain fatty acids are produced. There is now convincing evidence that these acids play an important role in maintaining a healthy bowel.

Diverticular disease

It is now recognised that constipation - and the resultant increase in pressure in the colon (large bowel) because of strained bowel movements - is the underlying cause of diverticular disease. In this disorder, small, blown-out pouches or sac-like swellings (diverticula) form in the wall of the colon and project into the abdominal cavity. Inflammation of these pouches is known as diverticulitis and may cause abdominal discomfort and pain.

Diverticular disease is very common in affluent societies, especially among elderly people. The treatment of constipation with high-fibre diets will not only help prevent the development of the disease, but will also improve - and may even 'cure' - an existing condition.

Colon cancer

Although the role of diet in the development of this disease is still unclear, some scientists believe that high energy and fat and low fibre intakes are important contributing factors (see Cancer - can Your Diet Make the Difference?, page 181). The way in which fibre may protect against colon cancer is probably very complex. It is thought that the rapid movement of a bigger volume through the large bowel shortens the bowel wall's exposure time to substances which may induce cancer (carcinogens).

Because of its bulking and water-binding effects, fibre dilutes the concentration of carcinogens in the gut. It may even bind these substances and help with their excretion in the faeces. New research has showed that butyric acid, one of the short-chain fatty acids produced from fibre fermentation in the large bowel, also protects the bowel against the development of cancer. In addition, changes in colonic pH as a result of the fermentation process may be of importance.

Where do you find dietary fibre?

By definition, only plant foods contain dietary fibre. Published values of fibre in foods vary greatly because of different analysis methods.

Wheat bran (commonly sold under the name of 'digestive bran') has the highest fibre content of all the items mentioned. Because of this, it should be regarded as a food supplement rather than as a food. (If you eat it as a food on its own - for example as a breakfast cereal - your fibre intake could in fact be too high!)

However, as shown above, an important result of the years of research into fibre is the realization that it can be used to lower the risk of some diseases and to treat them.

Can fibre help you lose weight?

Although there is as yet no firm evidence that fibre can be used to control weight problems, it can indirectly be of help if you're trying to cut down on kilojoule intake.

One of the effects of dietary fibre is that it 'dilutes' nutrients and therefore also the energy or kilojoule values of a food. In addition, foods which are rich in it need a good deal of chewing, which not only stimulates secretion of saliva but also means that it takes longer to eat them. In the stomach, insoluble fibre binds water and has a 'bulking' effect, while soluble fibre tends to form gels which slow down the emptying of the stomach contents into the small intestine. The result of these combined effects is that fibre-rich foods make you feel fuller for longer and less likely to head for the refrigerator half an hour after a meal! For this reason, and also to ensure that you get enough vitamins and minerals and won't suffer from constipation, any slimming diet should include ample fibre in the form of unrefined foods.

Effects of fibre in the small intestine

The small intestine is divided into the duodenum, jejenum and ileum and dietary fibre alters a number of functions throughout the area. Whereas refined foods are quickly digested and absorbed in the upper part or duodenum, fibre ensures that the food moves down into the jejenum and ileum, thus changing the site of digestion and absorption. The result is a slower and more prolonged or sustained absorption of several nutrients, which gives the body time to 'process' these nutrients.

In addition to water-binding and bulking effects, some fibre components have the ability to temporarily bind nutrients such as glucose and fats, as well as digestive enzymes, bile acids and possibly some toxic substances. This results in slower digestion of several nutrients and an increased excretion of bile acids - and perhaps also of poisonous substances.

How to increase your fibre intake

Having established that fibre has definite benefits to offer, how can you make sure you get enough of it on a regular basis? Basically, there are three ways of upping your fibre intake, namely:through following a natural high-fibre diet (lots of fruit and vegetables, wholewheat bread, unrefined rice, etc)by eating fibre-enriched foodsby taking fibre extracts or supplements in the form of bran, pills, tablets, powders or granules.

It probably goes without saying that the first option is the healthiest. A natural high-fibre diet in which more unrefined plant foods and less foods of animal origin are eaten, is preferable not only because it ensures adequate intakes of vitamins and minerals, but because it also includes less animal fat - whereas the pill-popping method will merely increase the intake of indigestible fibre.

Eating fibre-enriched products - such as some breakfa^st cereals and home-baked muffins to which bran has been added - will certainly increase fibre intake, but will not necessarily rectify dietary imbalances. This is because most South African recipes for wholewheat home-baked products contain too much fat and sugar, which may improve the flavour but also markedly increases the kilojoules. However, it is possible to cut both the fat and sugar content to healthier levels when baking at home.

Fibre extracts are useful in the treatment of disease. They should only be used for medical reasons and not as foods, and must be taken under the guidance of a physician or dietitian. Insoluble extracts such as bran should always be used in combination with adequate water intake to treat constipation and related diseases. Soluble extracts, such as konjac-glucomannan, pectin or guar gum, are used to lower blood cholesterol levels and to control glucose levels in diabetic patients.

How much is enough?

Recommendations for fibre intake are based on those of developed populations in the past (before the escalation of the diseases of affluence) and on intakes of population groups at low risk for these diseases - such as rural, less developed populations and vegetarians.

On average, affluent Western populations presently consume 10 to 20g total dietary fibre per day; it has been recommended that this should be increased to between 30 and 40g per day. Our own research has shown that white South Africans on a typically Western diet eat approximately 2g total dietary fibre per 1000 kilojoules (kJ) per day - a figure which should be doubled. Based on this recommendation, a fairly active adult woman with a daily energy need of between 8000 and 9000 kJ should take in 32 to 36g dietary fibre per day, while a moderately active adult man with an energy need of 9000 to 11000 kJ should consume 36 to 44g fibre.

The table below shows that you can obtain approximately 40g of total dietary fibre by eating six small to medium portions of wholegrain cereals (which include wholewheat bread, brown rice and unrefined breakfast cereals), one medium portion of legumes (beans, peas, lentils), three medium portions of vegetables and two medium portions of fruit per day.

Foods (and portion sizes) that will provide approximately 40 g total dietary fibre per day

Food	Portion size	Total amount (g)	Dietary fibre (g) -
4 medium slices"wholewheat bread	1 slice: 95 X 90 X 10 mm = 35 g	140	12,5
1 portion All
Bran Flakes	125 ml	25	7,5
1 portion cooked brown rice	125 ml	70	0,9
1 portion cooked dried beans	125 ml	100	7,4
1 portion cooked broccoli	125 ml	75	3,1
1 portion grated raw carrots	125 ml	95	2,4
1 portion mixed raw salad	125 ml	50	0,8
1 medium apple	52 X 66 mm	150	2,6
1 medium orange	65 X 70 mm	180	3,6
TOTAL			40,8

Can you eat too much fibre?

Many fibrous plants contain organic acids that bind minerals such as calcium, magnesium, zinc and iron. Although this has caused some concern in the past, there is no evidence that people who eat natural high-fibre diets (such as vegetarians) have low mineral levels, probably because this type of diet is particularly rich in vitamins and minerals. Including about 40g dietary fibre a day in your diet is regarded as being perfectly safe. However, where caution is necessary is in the taking of fibre extracts.

One of the lesser-known effects of fibre-rich diets is an increase in flatulence. When fibre ferments in the large intestine it produces odourless gases, which are not dangerous to health but can cause concern in some people. (Incidentally, offensive odour is caused by gases which are produced as result of the breakdown of other substances in the large bowel - such as sulphur-containing proteins - which have escaped digestion in the small intestine.)

Fibre extracts - handle with care!

If a natural high-fibre diet does not solve the problem of constipation, try taking not more than three tablespoons (9-12g) of digestive bran, divided into three dosages, on a daily basis. (If you don't like the taste of bran au nature], you can improve the flavour by baking it for three hours at 100 °C.) At the same time, increase your fluid intake to at least two litres per day and decrease excessive fat intake. This ensures adequate hydration of the 'extra' fibre.

Beware of over-enthusiatic dosage with fibre extracts or concentrates, as this can be harmful. As a general guideline, a third of the prescribed dosage should be taken for a week and two thirds for another week before the whole amount is taken.

The 'fibre message'

All in all, then, there is agreement that fibre forms an important part of a healthy, balanced diet. High-fibre diets are easy to follow and inexpensive if natural foods are eaten in their unrefined forms.

Guidance from and education by dietitians, nutritionists and doctors, as well as increased advertising of high-fibre products, have brought the 'fibre message' to some sections of our population.

Sadly, however, in other sections the situation is in reverse. As South Africa's rural black people grow increasingly urbanized, so their diets are becoming lower in fibre and higher in fat - and more and more, the so-called 'diseases of affluence' are being seen among them. For the 'fibre message' to have any significant effect on the health of the majority of our population, it must therefore also reach the very people whose diets once gave them natural protection against the degenerative diseases of Western civilization.

When all is said and done, education is only worthwhile when put into practice. So unless you, the consumer, choose high fibre, unrefined foods in preference to refined ones and unless pressure is put on manufacturers to produce the healthier alternatives, medical research and nutrition education will be of little use. Ultimately it is up to you to make your voice heard and to combat the influences of society, lifelong nutritional habits and perhaps simple apathy, in order to put the fibre message into practice.

Worthwhile Sources of Dietary Fibre (Food Cereals & Fibre rating)

• Bread, brown: Fair
• Bread, wholewheat: Good
• Wheat bran: Excellent
• Pronutro: Excellent
• Kelloggs All Bran Flakes: Excellent
• Kelloggs Cornflakes: Good
• Oats: Good
• Oat bran: Excellent
• Weet-Bix: Good
• Maize meal, white: Fair
• Maize meal, unsifted: Good
• Popcorn, plain: Good
• Rice, brown: Fair
• Ryvita, Ryeking: Good
• Provita: Good